[Minor] Enhance JIT kernel and add dev docs (#14570)

python/sglang/jit_kernel/__main__.py

@@ -0,0 +1,48 @@
+assert __name__ == "__main__"
+
+
+def generate_clangd():
+    import logging
+    import os
+    import subprocess
+
+    from tvm_ffi.libinfo import find_dlpack_include_path, find_include_path
+
+    from sglang.jit_kernel.utils import DEFAULT_INCLUDE
+
+    logger = logging.getLogger()
+    logger.info("Generating .clangd file...")
+    include_paths = [find_include_path(), find_dlpack_include_path()] + DEFAULT_INCLUDE
+    status = subprocess.run(
+        args=["nvidia-smi", "--query-gpu=compute_cap", "--format=csv,noheader"],
+        capture_output=True,
+        check=True,
+    )
+    compute_cap = status.stdout.decode("utf-8").strip().split("\n")[0]
+    major, minor = compute_cap.split(".")
+    compile_flags = ",\n    ".join(
+        [
+            "-xcuda",
+            f"--cuda-gpu-arch=sm_{major}{minor}",
+            "-std=c++20",
+            "-Wall",
+            "-Wextra",
+        ]
+        + [f"-isystem{path}" for path in include_paths]
+    )
+    clangd_content = f"""
+CompileFlags:
+  Add: [
+    {compile_flags}
+  ]
+"""
+    if os.path.exists(".clangd"):
+        logger.warning(".clangd file already exists, nothing done.")
+        logger.warning(f"suggested content: {clangd_content}")
+    else:
+        with open(".clangd", "w") as f:
+            f.write(clangd_content)
+        logger.info(".clangd file generated.")
+
+
+generate_clangd()